SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e97597b90dcef779bd8c0f0eaaca132ce6c3722b4b07ed979e37eefe2350a36' 
  AND token = 'M9lIMNHlOYgtaoixtOq0qBAm3r5LIsS5oU3Ny1qKCiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}